Circular surgical stapling device including buttress material

ABSTRACT

A buttress material and mounting structure assembly is provided for use with a circular surgical stapling device. The assembly comprises a ring-like mounting structure sized to have an outer diameter that frictionally engages a radial inner surface of a staple cartridge assembly, wherein the mounting structure is disposed within the radial inner surface of the staple cartridge assembly; an annular buttress material overlaying a tissue facing surface of the staple cartridge assembly, the annular buttress material defining an outer radial terminal edge extending radially beyond a pair of annular arrays of staple receiving slots, and a radial inner terminal edge extending across the mounting structure; and at least one suture securing the buttress material to the mounting structure.

CROSS-REFERENCE TO RELATED APPLICATION

The present application is a Continuation Application which claims thatbenefit of and priority to U.S. patent application Ser. No. 15/590,332,filed on May 9, 2017, which is a Continuation Application which claimsthat benefit of and priority to U.S. patent application Ser. No.14/064,280, filed on Oct. 28, 2013 (now U.S. Pat. No. 9,655,620), theentire content of which is incorporated herein by reference.

BACKGROUND Technical Field

The present disclosure relates to surgical stapling devices and buttressmaterials for use with said surgical stapling device and, moreparticularly, to structures and methods for attaching a buttressmaterial to a surgical stapling device for use in anastomosisprocedures.

Background of Related Art

Staples have traditionally been used to replace suturing when joining oranastomosing various body structures such as, for example, the bowel orbronchus. The surgical stapling devices employed to apply these staplesare generally designed to simultaneously cut and seal an extendedsegment of tissue in a patient, thus vastly reducing the time and risksof such procedures.

Linear or annular surgical stapling devices are employed by surgeons tosequentially or simultaneously apply one or more linear rows of surgicalfasteners, e.g., staples or two-part fasteners, to body tissue for thepurpose of joining segments of body tissue together and/or for thecreation of anastomoses. Linear surgical stapling devices generallyinclude a pair of jaws or finger-like structures between which bodytissue to be joined is placed. When the surgical stapling device isactuated and/or “fired”, firing bars move longitudinally and contactstaple drive members in one of the jaws, and surgical staples are pushedthrough the body tissue and into/against an anvil in the opposite jawthereby crimping the staples closed. A knife blade may be provided tocut between the rows/lines of staples. Examples of such surgicalstapling devices are described in U.S. Pat. Nos. 4,354,628, 5,014,899and 5,040,715, the entirety of each of which is incorporated herein byreference.

Annular surgical stapling devices generally include an annular staplecartridge assembly including a plurality of annular rows of staples,typically two, an anvil assembly operatively associated with the annularcartridge assembly, and an annular blade disposed internal of the rowsof staples. Examples of such annular surgical stapling devices aredescribed in U.S. Pat. Nos. 5,799,857 and 5,915,616 to Robertson et al.,the entirety of each of which is incorporated herein by reference.

In general, an end-to-end anastomosis stapler typically places an arrayof staples into the approximated sections of a patient's bowels or othertubular organs. The resulting anastomosis contains an inverted sectionof bowel which contains numerous “B” shaped staples to maintain a secureconnection between the approximated sections of bowel.

For most procedures, the use of bare staples, with the staples in directcontact with the patient's tissue, is generally acceptable. Theintegrity of the tissue will normally serve to prevent the staples fromtearing out of the tissue and compromising the sealing before healinghas occurred. However, in some surgical operations, surgical supports,e.g., meshes or buttress materials, are employed by surgeons incombination with linear stapling devices to bridge, repair and/orreinforce tissue defects within a patient, especially those occurring inthe abdominal wall, chest wall, diaphragm, and other musculo-aponeuroticareas of the body. Examples of suitable surgical supports are disclosedin U.S. Pat. Nos. 3,054,406, 3,124,136, 4,347,847, 4,655,221, 4,838,884,5,002,551, and 7,942,890, the entirety of each of which is incorporatedherein by reference.

When the staples are applied in surgical procedures utilizing surgicalsupports (i.e., reinforcing material), the legs of the staple typicallypass from the cartridge jaw through a layer of the surgical support, andthrough the patient's tissue before encountering the anvil jaw.

While the surgical supports described above are used in conjunction withlinear surgical stapling devices, the need exists for annular supportstructures for use in conjunction with annular or circular surgicalstapling devices, for example, an end-to-end anastomosis stapler such asa Model “EEA™” instrument available from COVIDIEN LP, New Haven, Conn.and disclosed in U.S. Pat. No. 5,392,979 to Green et al.

One possible side effect of any end-to-end bowel anastomosis is itstendency to undergo stenosis over time, which can decrease the diameterof the lumen over time. Accordingly, the need exists for an annularsurgical structure which operates in conjunction with any end-to-end,annular, or circular anastomosis or stapling device and assists inkeeping open the lumen of the anastomosed bowel or other tubular organover time.

A need also exists for an annular support structure which operates inconjunction with any end-to-end, annular or circular stapling device toreduce the trauma suffered by the patient, reduce the instances ofleakage, reduce the instances of bleeding, and create a relativelystrong bond between adjacent body tissues.

SUMMARY

The present disclosure relates to structures and methods for attaching abuttress material to a surgical stapling device for use in anastomosisprocedures.

According to one aspect of the present disclosure, a surgical staplingdevice for joining tissue portions is provided and includes a handleassembly; a tubular body portion supported on a distal end of the handleassembly, the tubular body portion having a staple cartridge assemblycontaining a plurality of surgical staples within a pair of annulararrays of staple receiving slots formed in a tissue facing surfacethereof, the staple cartridge assembly defining a radial inner surfaceand a radial outer surface; and an anvil assembly at a distal end of thesurgical stapling device, the anvil assembly having a shaft forremovably connecting the anvil assembly to the tubular body portion, theanvil assembly and tubular body portion being juxtaposed with respect toone another along the shaft and arranged so as to be approximated withrespect to one another.

The surgical stapling device further includes a ring-like mountingstructure sized to have an outer diameter that frictionally engages theradial inner surface of the staple cartridge assembly, wherein themounting structure is disposed within the radial inner surface of thestaple cartridge assembly; an annular buttress material overlaying thetissue facing surface of the staple cartridge assembly, the annularbuttress material defining an outer radial terminal edge extendingradially beyond the pair of annular arrays of staple receiving slots,and a radial inner terminal edge extending across the mountingstructure; and at least one suture securing the buttress material to themounting structure.

According to another aspect of the present disclosure, a buttressmaterial and mounting structure assembly is provided for use with acircular surgical stapling device including a staple cartridge assemblycontaining a plurality of surgical staples within a pair of annulararrays of staple receiving slots formed in a tissue facing surfacethereof, the staple cartridge assembly defining a radial inner surfaceand a radial outer surface. The buttress material and mounting structureassembly includes a ring-like mounting structure sized to have an outerdiameter that frictionally engages the radial inner surface of thestaple cartridge assembly, wherein the mounting structure is disposedwithin the radial inner surface of the staple cartridge assembly; anannular buttress material overlaying the tissue facing surface of thestaple cartridge assembly, the annular buttress material defining anouter radial terminal edge extending radially beyond the pair of annulararrays of staple receiving slots, and a radial inner terminal edgeextending across the mounting structure; and at least one suturesecuring the buttress material to the mounting structure.

The mounting structure may be fabricated from an elastomeric material.

Each suture may extend through the buttress material and through themounting structure.

Each suture may include a first end, a second end, and a bridge portioninterconnecting the first end and the second end, wherein the first endand the second end of each suture extends through the buttress materialand through the mounting structure.

The buttress material may define an annular inner attachment portion; anannular middle staple engaging portion, disposed radially outward of theinner portion; and an annular outer portion, disposed radially outwardof the middle portion.

Each suture may extend through the annular inner attachment portion ofthe buttress material. The first end and the second end of each suturemay extend through the buttress material and through the mountingstructure.

The bridge portion of each suture may extend in a direction transverseto a central axis of the buttress material.

A proximal and an outer corner of the mounting structure may bechamfered.

According to yet another aspect of the present disclosure, a method isprovided of using a buttress material and mounting structure assemblyfor use with a circular surgical stapling device including a staplecartridge assembly containing a plurality of surgical staples within apair of annular arrays of staple receiving slots formed in a tissuefacing surface thereof, the staple cartridge assembly defining a radialinner surface and a radial outer surface.

The method includes the steps of providing a buttress material andmounting structure assembly including a ring-like mounting structuresized to have an outer diameter that frictionally engages the radialinner surface of the staple cartridge assembly; an annular buttressmaterial overlaying the tissue facing surface of the staple cartridgeassembly, the annular buttress material defining an outer radialterminal edge and a radial inner terminal edge; and at least one suturesecuring the buttress material to the mounting structure.

The method further includes the step of positioning the buttressmaterial and mounting structure assembly at least partially within thecartridge assembly of the surgical stapling device such that themounting structure is disposed within the radial inner surface of thestaple cartridge assembly; and the outer radial terminal edge of theannular buttress material extends radially beyond the pair of annulararrays of staple receiving slots, and the radial inner terminal edge ofthe annular buttress material extends across the mounting structure.

The method further includes the steps of receiving body tissue betweenthe anvil assembly and the cartridge assembly; grasping the body tissuebetween the anvil assembly and the cartridge assembly; and firing thesurgical stapling device to drive a plurality of staples from the staplecartridge assembly through the buttress material and the body tissue;and sever the buttress material radially outward of the at least onesuture.

The mounting structure may be fabricated from an elastomeric material,and the step of positioning the buttress material and mounting structureassembly at least partially within the cartridge assembly of thesurgical stapling device may include the elastomeric mounting structureradially engaging the inner surface of the staple cartridge assembly ina press-fit manner.

Any of the above aspects of the present disclosure described may becombined with any other aspect of the present disclosure withoutdeparting from the scope of the present disclosure.

BRIEF DESCRIPTION OF DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of this specification, illustrate embodiments of the disclosureand, together with a general description of the disclosure given aboveand the detailed description of the embodiments given below, serve toexplain the principles of the disclosure, wherein:

FIG. 1 is a perspective view of an exemplary annular surgical staplingdevice according to the present disclosure;

FIG. 2 is a perspective view, with parts separated, of a head portion ofthe surgical stapling device of FIG. 1;

FIG. 3 is a further perspective view of the head portion of the surgicalstapling device of FIG. 1, illustrating a buttress material and amounting structure separated therefrom;

FIG. 4 is another perspective view of the head portion of the surgicalstapling device of FIG. 1, illustrating the buttress material connectedto the head portion;

FIG. 5 is cross-sectional view of the head portion and anvil assembly ofthe surgical stapling device of FIG. 1, as taken through 4-4 of FIG. 5,shown in position between a pair of body lumens;

FIG. 6 is an enlarged view of the indicated area of detail of FIG. 5;

FIG. 7 is a perspective, cross-sectional view, of a fastener accordingto another embodiment of the present disclosure, for securing thebuttress material to the mounting structure;

FIG. 8 is an enlarged view of the indicated area of detail of FIG. 7;

FIG. 9 is an enlarged perspective, cross-sectional view, of a fasteneraccording to another embodiment of the present disclosure, for securingthe buttress material to the mounting structure; and

FIG. 10 is a perspective view of the intestinal area of a patient,illustrating a method of positioning the annular surgical staplingdevice of FIG. 1 to connect the anvil assembly to the tubular bodyportion.

DETAILED DESCRIPTION OF EMBODIMENTS

Embodiments of the presently disclosed annular surgical stapling devicewill now be described in detail with reference to the drawing figureswherein like reference numerals identify similar or identical elements.As used herein and as is traditional, the term “distal” refers to thatportion which is furthest from the user while the term “proximal” refersto that portion which is closest to the user.

Referring initially to FIGS. 1 and 2, an annular surgical staplingdevice for use with a buttress material is disclosed herein and isgenerally designated as 10. Surgical stapling device 10 includes ahandle assembly 12 having at least one pivotable actuating handle member20, and an advancing member 22. Extending from handle member 12, thereis provided a tubular body or shaft portion 14 which may be constructedso as to have a curved shape along its length. Body or shaft portion 14terminates in a staple cartridge head assembly 16. Staple cartridge headassembly 16 is configured to receive a staple guide 60 therein. Stapleguide 60 includes at least one annular array of staple receiving slots62 defined in a distal end thereof and a plurality of staples 70disposed, one each, in each of staple receiving slots 62. For example,staple guide 60 may include one, two, or more than two annular arrays ofstaple receiving slots 62. Staple receiving slots 62 are defined in atissue facing or contacting surface of the distal end of the stapleguide 60.

Typically, staple cartridge head assembly 16 includes a staple pusher 53including a proximal portion having a generally frusto-conical shape anda distal portion defining two concentric rings of peripherally spacedfingers 52, each one of which is received within one of the respectivestaple receiving slots 62 of staple guide 60.

Additionally, staple cartridge head assembly 16 includes a knife 74,substantially in the form of an open cup with the rim thereof defining aknife edge, disposed within staple cartridge head assembly 16 andmounted to staple pusher 53. The knife edge is disposed radially inwardof the pair of annular arrays of staples 71 and the pair of annular rowsof staple receiving slots 62. Accordingly, in use, as the staple pusher53 is advanced, the knife 74 is also advanced axially in a lineardirection.

Positioned distally of staple cartridge head assembly 16 there isprovided, as seen in FIGS. 1 and 5, an anvil assembly 30 including ananvil member 32 and a shaft 34 operatively associated therewith forremovably connecting anvil assembly 30 to a distal end portion ofstapling device 10. Shaft 34 of anvil assembly 30 is connectable to acentral shaft 22 of stapling device 10 extending through staplecartridge head assembly 16 and connecting anvil assembly 30 to staplecartridge head assembly 16 of surgical instrument 10.

Reference may be made to U.S. Pat. No. 8,322,590 to Patel et al., theentire contents of which are incorporated herein by reference, for adetailed discussion of the construction and operation of annularstapling device 10.

Referring now to FIGS. 2-6, a buttress material 100 and a mountingstructure 120 together form an assembly for connecting buttress material100 to staple cartridge head assembly 16 is shown and will be described.Buttress material 100 is generally annular in shape and includes anannular inner attachment portion 102; an annular middle staple engagingportion 104, disposed radially outward of inner portion 102; and anannular outer portion 106, disposed radially outward of middle portion104. A substantially centrally located aperture 108, defined by an innercircumference of inner portion 102 is formed through or within buttressmaterial 100. Buttress material 100 may be any shape sufficient toprovide support for anastomosis of tissue after surgical stapling device10 has been fired including, for example, a rectangle, an oval, atriangle or any other polygonal or other shape.

As illustrated in FIGS. 3-6, buttress material 100 is sized such thatwhen buttress material 100 is positioned over the tissue contacting orfacing surface of staple guide 60, outer portion 106 of buttressmaterial 100 is substantially axially aligned with an outer surface ofstaple cartridge head assembly 16, and annular middle staple engagingportion 104 of buttress material 100 overlies staple retaining slots 62of staple guide 60. Aperture 108 of buttress material 100 is sized to atleast receive shaft 22 of anvil assembly 30 and central shaft 22 ofsurgical stapling device 10 therethrough. It is also contemplated thatbuttress material 100 may extend radially beyond an inner surface andthe outer surface of staple guide 60.

Buttress material 100 may be fabricated from surgical grade,biocompatible, non-absorbable material (i.e. permanent) or absorbablematerial (i.e. non-permanent), such as a mesh or other porous ornon-porous material desirably optionally containing, impregnated, orcoated with an adhesive, sealant and/or other medicament. It is alsocontemplated that each one or more portions of the buttress may be acomposite of include both a non-absorbable and an absorbable material.Suitable materials for the fabrication of buttress material 100 andsuitable adhesives, sealants, and/or medicaments for impregnation in orapplication to buttress material 100 may be found, for example, in U.S.Pat. No. 7,942,890, referenced above.

Buttress material 100 may be secured to staple head assembly 16 throughthe use of one or more fasteners or sutures 140 stitched to mountingstructure 120, as illustrated in FIGS. 2-6. Generally, each suture 140includes a first end or leg 140 a, a second end or leg 140 b, and a bodyor bridge portion 140 c extending between and interconnecting the firstand second ends 140 a, 140 b, as will be described in the embodiments tofollow.

Similar to buttress material 100, sutures 140 may be fabricated fromsurgical grade, biocompatible, non-absorbable material (i.e. permanent)or absorbable material (i.e. non-permanent) or material desirablyimpregnated with an adhesive, sealant and/or other medicament. It isalso contemplated that sutures 140 may be a composite of both anon-absorbable and an absorbable material. Suitable materials of sutures140 are described above with reference to buttress material 100 and maybe found, for example, in U.S. Pat. No. 7,942,890, referenced above.

As mentioned above, sutures 140 function to secure buttress material 100to mounting structure 120. Specifically, each of first and second ends140 a, 140 b of sutures 140 may extend through buttress material 100 andextend through mounting structure 120 and may be secured in place to oneanother through the use of knotting, fusing, heat welding, staking orother similar methods which will limit or prevent first and second ends140 a, 140 b of sutures 140 from being withdrawn through or frommounting structure 120. It is contemplated that bridge portion 140 c ofsutures 140 may rest against a tissue facing or contacting surface ofbuttress material 100 or against mounting structure 120.

While first and second ends 140 a, 140 b of sutures 140 are shown anddescribed as extending through mounting structure 120, it iscontemplated that first and second ends 140 a, 140 b of sutures 140 mayextend around mounting structure 140 and tie buttress material 100 tomounting structure 120.

As seen in FIGS. 2-6, mounting structure 120 is in the form of a ringthat is dimensioned to fit within a circumference of the inner wall 60 aof staple guide 60 of staple cartridge head assembly 16, in a press fitmanner. In an embodiment, ring 120 is formed from an elastomericmaterial and has a diameter so as to establish a degree of frictionbetween ring 120 and inner wall 60 a of staple guide 60 preventing orinhibiting mounting structure 120 from freely falling out of staplecartridge head assembly 16. It is envisioned that ring 120 may have asubstantially circular, transverse, cross-sectional profile, or, asshown in FIGS. 2, 5 and 6, may have a rectangular, transverse,cross-sectional profile. As seen in FIGS. 5 and 6, ring 120 may define achamfered corner 120 a along an outer and proximal edge thereof. In thismanner, the knife edge of knife 74 may first enter into the chamferedcorner 120 a of ring 120 upon firing and thus reduce any tendency ofring 120 to interfere or obstruct the firing of surgical stapling device10.

Being that ring 120 frictionally engages inner wall 60 a of staple guide60, with buttress material 100 stitched to ring 120 by sutures 140, whenring 120 is situated in staple guide 60, buttress material 100 overliesstaple retaining slots 62 of staple guide 60. Specifically, sutures 140are used to secure annular inner attachment portion 102 of buttressmaterial 100 to ring 120, and annular middle staple engaging portion 104of buttress material 100 overlies staple retaining slots 62 of stapleguide 60.

In use, when surgical stapling device 10 is fired, and staple pusher 53and knife 74 are advanced, staple pusher 53 expels staples 70 fromstaple retaining slots 62 of staple guide 60 and into buttress material100, and knife 74 severs buttress material 100 between annular innerattachment portion 102 and annular middle staple engaging portion 104.By severing buttress material 100 between annular inner attachmentportion 102 and annular middle staple engaging portion 104, innerattachment portion 102 may be removed from the surgical site togetherwith surgical stapling device 10, and annular middle staple engagingportion 104 (together with outer portion 106) is secured to theunderlying tissue by staples 70.

Turning now to FIGS. 7 and 8, a fastener for securing buttress material100 to mounting structure 120, according to another embodiment of thepresent disclosure, is generally designated as 240. Fastener 240includes a ring-like body or frame portion 242 having a radial dimensionso as to overlie annular inner attachment portion 102 of buttressmaterial 100. Fastener 240 further includes a plurality of barbed pins244 extending from frame portion 242, in a direction parallel to acentral axis “A” of frame portion 242, and in a proximal direction fromframe portion 242.

In use, barbed pins 244 penetrate through buttress material 100 andpenetrate into or are potted into elastomeric mounting structure 120 tothereby hold buttress material 100 in place relative to mountingstructure 120.

Turning now to FIG. 9, a fastener for securing buttress material 100 tomounting structure 120, according to yet another embodiment of thepresent disclosure, is generally designated as 340. Fastener 340includes a pin or stem 344 integrally formed with and extending frommounting structure 120. Pins 344 extend from mounting structure 120 in adirection parallel to a central axis of mounting structure 120, and in adistal direction from mounting structure 120. Each pin 344 terminated ina mushroomed head portion 346 that is configured and dimensioned to passthrough an aperture, slit or the like formed in buttress material 100,specifically, formed in annular inner attachment portion 102 of buttressmaterial 100.

In use, head portion 346 of fastener 340 extends through buttressmaterial 100 to thereby hold buttress material 100 in place relative tomounting structure 120.

Turning now to FIG. 10, there is illustrated the use of annular surgicalstapling device 10 and detachable anvil assembly 30 in an anastomosisprocedure to effect joining of adjacent intestinal sections “T1 and T2”.The anastomosis procedure is typically performed using minimallyinvasive surgical techniques including laparoscopic means andinstrumentation. At the point in the procedure shown in FIG. 10, adiseased intestinal section has been previously removed, anvil assembly30 has been applied to the operative site either through a surgicalincision or transanally and positioned within intestinal section “T2”,and staple cartridge head assembly 16 of surgical stapling device 10 hasbeen inserted transanally into intestinal section “T1”. Intestinalsections “T1 and T2” are also shown temporarily secured about theirrespective components (e.g., shaft 34 of anvil assembly 30, and thecentral shaft 22 of staple cartridge head assembly 16 of surgicalstapling device 10 by a purse-string suture or the like).

According to one method, with reference to FIG. 10, buttress material100 may be positioned and secured to the tissue contacting or facingsurface of staple guide 60 of staple cartridge head assembly 16 usingany of the mounting structures 120 described above. It is envisionedthat staple cartridge head assembly 16 and/or surgical stapling device10 may come with buttress material 100 pre-positioned and secured to thetissue contacting or facing surface of staple guide 60 of staplecartridge head assembly 16. Alternatively the surgeon may securebuttress material 100 to the tissue contacting or facing surface ofstaple guide 60 of staple cartridge head assembly 16 prior to use.

With buttress material 100 secured in place, the surgeon maneuvers anvilassembly 30 until the proximal end of shaft 34 is inserted into thecentral shaft 22 of staple cartridge head assembly 16 of surgicalstapling device 10. Central shaft 22 is now engaged to shaft 34 withintestinal sections “T1 and T2” disposed between anvil assembly 30 andstaple cartridge head assembly 16. As seen in FIGS. 5 and 10, forexample, buttress material 100 is disposed between head assembly 16 andintestinal section “T1”.

Anvil assembly 30 and staple cartridge head assembly 16 are thenapproximated to approximate intestinal sections “T1 and T2”. Surgicalstapling device 10 is then fired to staple buttress material 100 andintestinal sections “T1 and T2” together, and the knife 74 is actuatedto cut the portion of tissue and any portion of buttress material 100(i.e., inner portion 102), to complete the anastomosis. Once anastomosisis complete anvil assembly 30 and staple cartridge head assembly 16 areunapproximated to release intestinal sections “T1 and T2” and buttressmaterial 100 sandwiched therebetween.

In accordance with the present disclosure, it is envisioned thatsurgical stapling device 10 may be modified for use with a poweredactuation assembly. Commonly owned U.S. Pat. No. 8,806,973, the contentof which is incorporated by reference herein in its entirety, disclosesa surgical device having a powered actuator assembly including powereddrive members.

Although the illustrative embodiments of the present disclosure havebeen described herein with reference to the accompanying drawings, theabove description, disclosure, and figures should not be construed aslimiting, but merely as exemplifications of particular embodiments. Itis to be understood, therefore, that the disclosure is not limited tothe precise embodiments described herein, and that various other changesand modifications may be effected by one skilled in the art withoutdeparting from the scope or spirit of the present disclosure.

1. (canceled)
 2. A surgical stapling device for joining tissue portions,comprising: a cartridge assembly including: a staple guide configured toreleasably receive a surgical staple; and a knife disposed within thecartridge assembly and configured to axially translate therethrough; ananvil assembly mounted at a distal portion of the cartridge assembly,the anvil assembly configured to move relative to the cartridge assemblybetween a spaced-apart position and an approximated position; a mountingring disposed within the cartridge assembly such that the mounting ringis coaxially positioned relative to the staple guide, the mounting ringincluding a distal portion configured to receive at least one firstportion of an annular buttress material; and a ring-like retaineroverlying the annular buttress material and concentric with the mountingring, wherein the ring-like retainer is secured to the mounting ringwith the annular buttress material interposed therebetween.
 3. Thesurgical stapling device according to claim 2, wherein the ring-likeretainer includes at least a pair of barbed pins projecting from aproximal surface thereof, extending through the annular buttressmaterial, and potted into the mounting ring.
 4. The surgical staplingdevice according to claim 3, wherein the at least a pair of barbed pinsincludes an annular array of barbed pins.
 5. The surgical staplingdevice according to claim 3, wherein the ring-like retainer defines aninner diameter that is larger than an inner diameter of the annularbuttress material.
 6. The surgical stapling device according to claim 5,wherein the mounting ring defines an inner diameter that is larger thanthe inner diameter of the annular buttress material.
 7. The surgicalstapling device according to claim 6, wherein the inner diameter of thering-like retainer is larger than the inner diameter of the mountingring.
 8. The surgical stapling device according to claim 7, wherein thering-like retainer defines an outer diameter that is smaller than anouter inner diameter of the mounting ring.
 9. The surgical staplingdevice according to claim 2, further comprising: a central shaftextending through the cartridge assembly, wherein the anvil assemblyincludes an anvil shaft configured to removably connect the anvilassembly to a distal portion of the central shaft extending through thecartridge assembly.
 10. The surgical stapling device according to claim2, wherein the staple guide includes an annular array of staplereceiving slots and the knife includes a knife edge disposed radiallyinward of the annular array of staple receiving slots.
 11. The surgicalstapling device according to claim 2, wherein the staple guide includesa radial inner surface and the mounting ring includes an outer diameterconfigured to frictionally engage the radial inner surface of the stapleguide when the mounting ring is coaxially positioned relative to thestaple guide.
 12. The surgical stapling device according to claim 10,wherein the staple guide includes a tissue facing surface configured toreceive at least one second portion of the annular buttress materialsuch that the at least one second portion of the annular buttressmaterial extends radially outward beyond the annular array of staplereceiving slots and the at least one first portion of the annularbuttress material extends radially inward across the distal portion ofthe mounting ring.
 13. The surgical stapling device according to claim2, wherein the mounting ring is formed of an elastomeric material. 14.The surgical stapling device according to claim 10, wherein the mountingring includes a proximal portion having a chamfered edge, wherein thechamfered edge of the mounting ring is positioned to facilitate axialtranslation of the knife distally beyond the mounting ring.
 15. Thesurgical stapling device according to claim 14, wherein the mountingring is chamfered along an outer corner thereof.
 16. The surgicalstapling device according to claim 15, wherein the chamfered corner ofthe mounting ring is disposed radially inward of the knife edge of theknife.
 17. The surgical stapling device according to claim 14, whereinthe knife edge of the knife is disposed radially between the annulararray of staple receiving slots of the staple guide and the chamferededge of the mounting ring.
 18. The surgical stapling device according toclaim 2, further comprising: a handle assembly; and a tubular bodysupported on a distal end portion of the handle assembly, wherein thecartridge assembly is mounted on a distal end portion of the tubularbody.
 19. A surgical stapling device for joining tissue portions,comprising: a cartridge assembly including: a staple guide configured toreleasably receive a surgical staple, the staple guide defining an innerannular wall having a diameter; and a knife disposed within thecartridge assembly and configured to axially translate therethrough; ananvil assembly mounted at a distal portion of the cartridge assembly,the anvil assembly configured to move relative to the cartridge assemblybetween a spaced-apart position and an approximated position; a mountingring disposed within the cartridge assembly such that the mounting ringis coaxially positioned relative to the staple guide, the mounting ringhaving a diameter greater than the diameter of the inner annular wall ofthe staple guide, wherein the mounting ring is frictionally securedwithin the staple guide; an annular buttress material overlying at leasta portion of the cartridge assembly and the mounting ring; and aring-like retainer overlying and concentric with the mounting ring,wherein the ring-like retainer is secured to the mounting ring with theannular buttress material interposed therebetween.
 20. The surgicalstapling device according to claim 19, wherein the ring-like retainerincludes at least a pair of barbed pins projecting from a proximalsurface thereof, extending through the annular buttress material, andpotted into the mounting ring.
 21. The surgical stapling deviceaccording to claim 20, wherein the mounting ring is formed of anelastomeric material.